The cherub angel (C. argi) is the angel your referring to, I would expect the closeness in coloration to be a war starter. The brazzilian flameback (C. arauntonotus) is almost indistinguishable from the African (C. acanthops) and I truely believe C. argi is some sort of hybrid from C. aurauntonotus, if not the same fish, just with slight environmental evolutionary changes. I have successfully kept 4 C. argis together in a 200g aquarium, so maybe there is a chance.